Colon cancer symptoms present in various ways: Rectal bleeding or blood in stool are some of the signs of colon cancer. It is a sign that some form of erosion of the bowel wall has taken place.
However, benign polyps can also bleed and so can hemorrhoids or anal fissures. None of these other causes of bleeding are due to cancer, but it does mean that a doctor needs to check any of these patients out until it is clear what is going on. A tumor in the rectum can bleed profusely and the patient needs to be brought to the Emergency Department of the nearest hospital, as a blood transfusion may be needed. Colonoscopy or sigmoidoscopy has to be done on an emergency basis to find the source of bleeding and stop it (Ref 1, 2 and 3).
In another case the colon tumor may have quietly grown so big that it closes off the entire bowel opening. This is called a bowel obstruction and often cancer of the colon can be the cause, particularly in the sigmoid colon. The patient may vomit material, which has a fecal smell. At the same time there is acute abdominal pain in the region of where the bowel obstruction is. This patient needs to be hospitalized as well.
The group of patients who are picked up on an emergency basis and then diagnosed with the underlying cancer of the colon have survival rates that are 22% worse than patients where the cancer has been picked up through one of the screening methods (stool for occult blood or colonoscopy). The reason for this is that these patients who are more symptomatic also have more advanced disease with more regional and distant metastases. This translates into a poorer prognosis despite adequate treatment.
1. Cancer: Principles &Practice of Oncology, 4th edition, by V.T. De Vita,Jr.,et. al J.B.LippincottCo.,Philadelphia, 1993.Vol1. Chapter on Cancer of the colon.
2. Cancer: Principles&Practice of Oncology. 5th edition, volume 1. Edited by Vincent T.DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter 32, Section 7: Cancer of the colon.
3. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 34, page 328-330.
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